An Aspect of Quantum Antiferromagnetism on a Square Lattice

Abstract

We propose an accurate expression for the ground state of spin —1/2 Heisenberg antiferromagnetic system on a square lattice in order to understand the properties of the quantum ground state, on the basis of the extended RVB picture where a singlet pair with longer distance than nearest neighbor (NN) is taken into account as well as that for NN. Quite a few parameters introduced in consideration of geometrical properties for each RVB in a square lattice of spin number N ≤ 26 is determined by the variational procedure. The agreement to numerical solution obtained by exact diagonalization is quite well. Properties of the ground state are discussed on the basis of such an agreement, in connection with the problem of Néel-like correlation containing the quantum fluctuation.KeywordsVariational FunctionHigh Temperature SuperconductivityNear NeighborTrial FunctionQuantum FluctuationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.